1. Field of the Invention
This invention relates to an improved endless power transmission belt construction for a continuously variable transmission and to a transverse belt element therefor as well as to methods of making the belt construction and the belt element.
2. Prior Art Statement
It is known to provide a belt construction for a continuously variable transmission wherein the belt construction comprises an endless flexible band means and a plurality of belt elements carried by the band means in sliding relation therewith, each belt element having slot means receiving the band means therein and having opposed faces disposed in compressed relation against adjacent faces of adjacent belt elements. Such belt elements are formed from metallic material. For example, see the U.S. Patent to Doorne et al, U.S. Pat. No. 3,720,113; the U.S. Patent to Aberson, U.S. Pat. No. 4,299,586 and the U.S. Patent to Vollers, U.S. Pat. No. 4,080,941.
While it is applicants' belief that no one has provided such a belt construction wherein all of the belt elements are formed substantially solely from a high performance polymeric material that has high heat resistance, high compressive modulus, high toughness and high strength according to the teachings of this invention, the U.S. Patent to Hattori et al, U.S. Pat. No. 4,338,081 has every other belt element between the driving metal belt elements thereof formed as a non-driving belt element and formed of "non-metallic material having excellent compression resistance, such as synthetic resin, carbon graphite, synthetic resin containing carbon graphite fibers, and hard rubber so that the weight of the torque transmission belt can be reduced." It should also be noted that this U.S. Pat. No. 4,338,081 while describing that the main belt elements are formed of tool steel states "Furthermore, the main blocks 7 can be made of material other than tool steel if it has the sufficient strength and abrasion resistance required in torque transmitting means of this type."
It is also known to provide a belt construction for a continuously variable transmission and comprising an endless flexible band means and a plurality of belt elements carried by the band means in sliding relation therewith, each belt element having slot means receiving the band means therein and having opposed faces disposed in compressed relation against adjacent faces of adjacent belt elements. Each belt element has opposed sides for respectively engaging pulley faces of the transmission. The slot means for each belt element defines a pair of slots respectively interrupting the opposed sides thereof and being spaced from each other by a central stem portion of the element. The pair of slots for each element receive parts of the band means therein and respectively define a pair of shoulders engaging the parts of the band means, each shoulder of each belt element having an arcuate transverse crown surface provided with an apex that engages its respective part of the band means. For example, see the aforementioned U.S. Patent to Vollers, U.S. Pat. No. 4,080,841, wherein it appears in FIG. 3 thereof that the apexes of the surfaces 9 are each disposed in the center of its respective transverse shoulder.